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thermomate

Tankless Water Heater Electric 27kW at 240 Volt, ThermoMate On Demand Instant Hot Water Heater Up to 6.4GMP, Self-Modulating Energy Saving for Residential Indoor Shower, Draw 114Amp

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Availability: In Stock.
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Arrives Monday, Aug 3
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Set name: ET-27kW


Features

  • [Important] - This 27kW Heater Draws max 114Amp currrent which must requiring 3 dedicated Double-pole 40AMP Circuit Breakers using 3 x 8AWG wiring and strongly recommend 200Amp Household Service for stable use
  • [Instant Unlimited Hot Water] - On demand tankless electric water heater, providing hot water in 3 seconds when you need it and as long as you need, eliminating wait time, never run out of hot water again and No More cold shower. Flow Rate 5.27GPM @35F Rise.
  • [Self-modulating Power] - Self-modulating technology regulating the amount of energy required to heat water only when you need it with 99.8% efficient, saving up to 60% on water heating cost comparing to traditional tank water heater. Wall mounted compact size with no water tank, convenient for any spaces, saving floor space and fitting into tight spaces.
  • [Easy Installation & Safety Protection] - ETL certified with overheating protection, auto stop heating when detecting no water, quality workmanship for leakage protection
  • NOTE - Make sure this water heater is the correct size for your hot water need: 27kW 208 ~ 240V (adjustable) draw max 114Amp; Required breaker: 3 x Double-POLE 40AMP; Wire gauge 3 x 8AWG; Unit size 17.12" x 13.12" x 3.12"; Water connection 3/4" NPT

Description

Whether shower and baths, laundry and dishes, or shaving and hand washing, for home or business, with dedicated advanced technology and years of experiences in hot water solution, ThermoMate’s new line of tankless electric water heaters provide you a hot water system you can count on, every day, for years to come. Energy efficient, easy installation, compact size, endless hot water, consistent water flow, perfet for point of use, booster, or whole house needs NO need to wait for water getting ready for a shower. NO sudden cold water during your shower. Stable flow technology provide you immediate hot water for as long as you need and anytime you want. Auto adjust power to ensure constant temperature output. Save as much as 60% on your electric bill compared to the traditional tank water heater. Electric tankless unit only heat water that you use, eliminating standby heat loss. Also with auto modulating technology and 99.8% heating efficiency, use only necessary power to heat water efficiently Traditional whole house tank water heater is so bulky that it can only be placed in your garage or basement, which is far from your main water use point. Our lightweight and easy-to-install electric tankless water heaters can be mounted in small or tight spaces throughout your home ET270 ET240 ET180 ET110 ET140 ET110HC ET080 Develop cutting-edge heating products ThermoMate is committed to pioneering heating solutions that not only enhance comfort but are at the forefront of energy-efficient technology. From efficient water heating for the kitchen and bathroom to space heating that make Outdoor/indoor livings more comfortable. ThermoMate upholds the highest standards of reliability and ethical integrity, ensuring our products and practices consistently earn your trust and exceed expectations. Visit the Store Visit the Store Visit the Store

Brand: thermomate


Power Source: 208~240V Hardwire


Product Dimensions: 13.12"W x 17.12"H


Special Feature: Instant hot water, Leaking free & Maintenance free heating element


Color: Gray


Power Source: 208~240V Hardwire


Special Features: Instant hot water, Leaking free & Maintenance free heating element


Wattage: 27 KW


Voltage: 240 Volts (AC)


Flow Rate: 5.27 Gallons Per Minute


Maximum Temperature: 140 Degrees Fahrenheit


Heat Output: 27 Kilowatts


Maximum Pressure: 150 Pound per Square Inch


Mount Type: Wall


Is Electric: Yes


Item Dimensions W x H: 13.12"W x 17.12"H


Item Depth: 3.12 inches


Material Type: Metal


Brand Name: thermomate


Model Number: ET270


Manufacturer: thermomate


UPC: 750139327607


Manufacture Year: 2024


Included Components: Mount Kit


Item Type Name: tankless water heater


Manufacturer Part Number: ET270


Color: Gray


Style Name: 27kW


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Aug 3

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Amazing water heater, good things do come in small packages
Set name: ET-18kW
***UPDATE*** Month 1 after installing the unit, my electric bill went from $350 the prior month down to $230 the following month. So this has had clear and immediate cost savings for my electrical usage. Very happy with the results! ---------------------- I wanted to replace my traditional tank water heater with an electric tankless, so I did hours of research and comparing models and options. Finally settled on this unit in the 18KW size to fit my needs. I wanted to the next higher up but my electrical panel and home service capacity made that a risk choice. However, I'm delighted at how well the 18kw model works for my whole home use-case. Thankfully due to having an EV, I already had a conveniently located sub-panel installed. All I had to do was upgrade the capacity on that sub-panel, which was as simple as buying a larger breaker and making sure the existing wiring was up to the task. Ended up taking out the old 30amp breaker the tank water heater used out of the main panel, installing a 40-amp dual pole breaker there in its place, then upgraded my sub-panel to 100amps, and finally installing the second 40-amp dual pole breaker in the sub-panel. Ran all the 8 AWG wire to the location where I wanted to mount the water heater and used an appropriate amount of conduit and secured to the wall, which for me thankfully was only about 6 feet of distance. If you have complex electrical situations happening, definitely call in a licensed electrician. At this point it was an easy install to mount the unit on the wall, secure the wiring which was intuitive, and wall labeled. I didn't find any of the wiring or instructions to be wrong or confusing so thats a plus. The moment of truth then arrived, powering on the unit and setting the desired water temperature. A few quick tests and bingo, hot water. Its not been 3 days since the install and multiple showers, laundry, running the dishwasher, etc. No issues whatsoever. In fact, this unit outperforms the tank water heater we had before. My family now reports that they have to set the faucet to a less hot position than they did previous during showers. The water flow is perfect even when both showers are running full blast. We get consistently hot water and don't have to adjust it multiple times during the course of the shower as we did with the old water heater. Overall, very happy with the performance of this unit! My application is a single story, 2 full bath home, so I wanted something that could handle two concurrent showers and the occasional hand washing or laundry running at the same time. And I'm thrilled to say that it works for me better than expected. I also love that its a newer design that separates the heating element from the water flow path, which means less maintenance and easier repairs if something goes wrong in the future. Time will tell in terms of durability, but I was impressed with the quality of the build, its well-made and appears to be a thoughtful and clean design. Other units I checked out before buying this one looked sloppy, not as well designed. I'm so glad I chose this model. Obviously do your research on your electrical capacity, sizing for your use-case, etc. All I can say is that it works for me in my whole house use-case in Central Florida. Northern cold climates may need a more powerful unit. For me, I've got no doubt this will be more efficient and save me money on my monthly electric bill compared to the old unit electrical consumption. To top it all off, I got this on Amazon Prime Day using a deal and the cost was unbeatable for what I got in this unit. Super happy, will update the review in the future should anything else happen to change my mind. ... show more
Reviewed in the United States on October 17, 2023 by Joe
    • Works well with hard water
Set name: ET-24kW
So far, i'm liking this unit to its Rheem counter part... I have hard water we joke about it being liquid rock. But this unit so far has been rather nice, performs well, might take a couple seconds longer to warm up, but it gets it nice and hot.. Now its the longevity game i'm gonna see.. Looks like more electronics in this device than the rheem, but maybe they will hold up. Water flow is nice and the installation was pretty normal for the unit, 8 gauge wire etc, just wish it came preslotted for a larger single conduit to make my previous setup compatible, but after trial and error, I got it .... Its a nice small little unit, you can install it anywhere really.. I'd suggest somewhere near but far enough from the breaker panel as the wire is stupid expensive these days.. But if money isn't an issue put it where it works for you. ... show more
Reviewed in the United States on May 12, 2026 by MicahinTN
    • It's small and light but it's just right!
Set name: ET-14kW
Review Image by JD Stewart
I bought this ThermoMate 14kW 240 VAC tankless water to replace a 50 gallon tank for a friend of the family that had burnt out. We tried replacing the burners, but they kept burning out, too. The wiring itself was questionable (I didn't install the old tank, I just had to try to fix it. I gave up and found this one on Amazon. Mounting was really easy due to its small size. I did have to run new #6 line, get a new StabLok 60A breaker, and create proper drains for the flush. Other than that, this was the easiest tankless install I've ever done. Their house is pretty small, so it produces the perfect amount of hot water for the single mom and disabled daughter. It functions perfectly and has great water flow. She does have a GoFund me to get help funding the replacement of all the wiring, interfaces, and circuit panels in the house. The house was wired back in the 40's, so there are no grounds to any outlets, lights, or electrical devices. She's had several electricians look at the wiring and all agree the home is a fire hazard. Even Idaho Power refuses to help to protect THEIR lines. Please DM me if you would like to help. I'll send you a link or look for "protect-letitias-home-from-fire-hazards". ... show more
Reviewed in the United States on October 6, 2025 by JD Stewart
    • You need an electrician to do the electrical work for your local electrical codes.
Set name: ET-18kW
Good quality works very good no issues and easy to install the plumbing. But you do have to add the additional electrical circuits with cut off boxes for each 40 amp line.
Reviewed in the United States on April 11, 2026 by Gamboa
    • GIVES LL ERROR CODE RANDOMLY IN WINTER. CANT HANDLE COLD WATER?!
Set name: ET-24kW
keeps shutting off with "ll" error code. what good is a tankless water heater that wont heat water in winter? basements 60 degrees. the coldest water temp is 47-55 degrees. according to the manual its supposed to shut off if the water is 37 degrees or colder. well... the units at least 10 degrees off. hot garbage unit. worked fine for 4 months. we have tried putting flow limiters, nothing seemed to help. must be defective. we have a dual shower head bath. both are "low water usage" heads. it ran fine for a month. then as temps dropped it randomly decided to be picky how we use our hot water. ... show more
Reviewed in the United States on February 22, 2026 by jase
    • Space-Saving - Totally Worth It!!
Set name: ETH-11kW
Review Image by DANAE C.
Review Image by DANAE C.
This tankless water heater has been a great upgrade!! It saves so much space compared to my old one. I’m already noticing the benefits of having instant hot water on demand. Installation was straightforward, the controls are easy to use, and I love the LED display. It feels efficient and modern, and I’m hopeful it will also save on energy costs over time 🙏🏼 Honestly, I wish I had switched to a tankless system sooner. If you’re considering one, this is a fantastic option - both in quality and price! ... show more
Reviewed in the United States on January 30, 2026 by DANAE C.
    • Great Product
Set name: ET-27kW
Review Image by Randy Johnson
This tankless water heater offers excellent quality at an exceptional price. Installation was simple, and it has performed flawlessly from day one. What stands out most is the noticeable reduction in my electricity bill since switching to this system. In just two years, it has more than paid for itself. I took a chance moving from a traditional water heater to a tankless model, but it turned out to be one of the best decisions I’ve made. ... show more
Reviewed in the United States on February 5, 2026 by Randy Johnson
    • So happy to have heated water again!
Set name: ET-14kW
Review Image by Yahweh's Vessel
Setup was kinda easy but difficult at the same time. My husband needed my dad's help. You get to lower or increase your temperature. Very happy to have it after going without heated water for a couple of months. Came securely and perfect shape and on time. Very space efficient. Water flow is great! Seems durable. Prayerfully it will work for years and years. ... show more
Reviewed in the United States on February 15, 2026 by Yahweh's Vessel

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